The angioarchitecture of a monochorionic placenta is characterised by the presence of vascular connections between the circulations of the fetuses. The combination of number and type of vessels involved are unique to each pregnancy. The net effect is a dynamic bidirectional flow of blood between the co-twins. The presence of vascular connections creates unacceptable risks for using intra-fetal injection as a method for selective termination.When intrauterine death of one fetus occurs, the risk of death or cerebral damage in co-twin increases, likely because of acute exsanguination of the survivor into the lower pressure circulation of the dead twin through the placental anastomoses. Hypotension and hypoxia then lead to under-perfusion of the co-twin, causing tissue damage. In complicated monochorionic pregnancies, selective termination can be advocated as a therapeutic alternative to termination of the entire pregnancy. A variety of occlusive techniques have been used to achieve selective termination in monochorionic twin pregnancies, including bipolar cord coagulation. laser cord coagulation, and cord ligation. These techniques require the insertion of a relatively large diameter instrument through a 3.8 mm operative sleeve into the amniotic sac of the fetus to be terminated, creating a significant risk for membrane complications, haemorrhage, and preterm labor. Bipolar cord coagulation is preferred when enough amniotic fluid allows for insertion sleeve and deployment of the device. Monoamniotic twin cases are best performed with bipolar cord coagulation because of the need for cord transection to prevent complications from cord entanglement once the termination is completed. If the cord segment to the demised fetus is left intact, it can act as a weight that can cause compression of the surviving twins cord. Our patient is monochorionic diamniotic twins in 18th weeks. One fetus has NTD and hydrocephaly. We performed bipolar cord coagulation for that fetus in this week. The easiest non-transplacental access was chosen, with the aim of approaching the umbilical cord at a 45 degree angle at its placental insertion. The cannula with the trocar was inserted into pocket of amniotic fluid that allowed the forceps to be opened and the cord grasped. Coagulation was performed at power settings of 50 W applied for 10-30 seconds. The procedure was deemed successful when echogenic bubbles were seen coming from the cord and cord itself appeared hyperechogenic. Confirmation of the occlusion was also provided by the absence of detectable color Doppler flow in the distal part of the cord, with at least 2 min of persistent asystole. The entire procedure lasted for 15-40 min. Cardiac activity of the co-twin monitored during the entire procedure and immediately afterwards, and MCA-PSV was also recorded to detect fetal anemis. Cerebral MRI of the survivng twin was also normal 2 weeks after the procedure.The patient is in 24.th weeks of pregnancy.
Keywords
Monochorionic twins, fetal discordant anomaly, bipolar cord coagulation.
